Electric discharge tube comprising electrodes secured to rods



Jan. 11, 1949. J. c. JANSSEN 2,458,945

ELECTRIC DISCHARGE TUBE COMPRISING ELECTRODES SECURED TO RODS Filea Jan. 15, 1946 INVENTOR.

JOJEMMS CORNELISJZNSSHV ATIORNEY. i

Patented Jan. 11, 1949 ELECTRIC DISCHARGE TUBE COMPRISING ELECTRODES SECURED TO RODS Johannes Cornelis J anssen, Eindhoven, Netherlands, assignor, by mesne assignments, to Hartford National Bank and Trust Company, Hartford,Conn., as trustee Application January 15, 1946, Serial No. 641,302

In the Netherlands March 18, 1942 I 9 Section 1, Public Law 690, August 8, 1946 Patent expires March 18, 1962 It is known to secure electrodes and other internal parts of electric discharge tubes to rods. This construction frequently occurs with cathode ray tubes but it may also be used in other tubes comprising a series of electrodes or screens, as rectifying tubes, multiplying tubes, etc. In cathode ray tubes the electrode system is frequently secured to a certain number of rods arranged in parallel with the axis of the tube. A rigid system is thus obtained of which the components cannot be easily brought out of position by a stroke or impact.

In one of the known constructions the rods are of glass, the electrodes being secured thereto by softening the glass and pressing the supporting members of the electrodes into the glass so that after cooling the glass the supporting members are rigidly fastened in it. This construction has the drawback that asymmetrical deformations of the rods frequently occur, resulting in the e1ectrodes being slightly displaced relatively to each other. The exact centering of the electrodes then is destroyed and this may lead to all sorts of errors in the focusing of the ray, such as astigmatism.

In constructions other than that utilizing rods the pressin of supporting members into glass may also involve the above-mentioned drawback, though constituting otherwise a very rigid method of fastening. The present invention has for its purpose to provide a satisfactory fastening of electrodes and other internal parts of discharge tubes whilst avoiding this drawback.

In a tube according to the invention the carrying members are provided with cavities containing a hardened mass in which supporting members of the fastened objects are set. These supporting members may be rings or discs, between the surfaces of which the electrode system is arranged. They may also be rods as referred to in the preamble. In the latter case the fastening according to theinvention differs from that in' tubes with sealed glass rods in that the supports for the electrodes are not set directly into the material constituting the rods but arearranged in a filling mass provided in the cavities of the rods.

For each support to be placed in the carrying member the latter may have a separatecavity at the place reserved therefor. In the case of rods, however, it is more efficient to make the cavities in the form of longitudinal grooves. This offers the advantage that the electrodes may be secured to the rods at any desired height and the 7 Claims. (Cl. 250-27.5)

2 same carrying rods may be used for different types of tubes.

In one very suitable construction the groove at .the mouth is narrower than farther towards the interior. In this construction the filling mass is better retained in the rod than' with a groove which at the mouth is widest or throughout equally wide. In this case the rods may have the shape of tubes having a longitudinal seam.

The rods should be made of a material having a high melting point or softening point, as quartz or if necessary hard glass. It is still better to utilize a ceramic material, as steatite or magnesium silicate. It is also possible to utilize metal rods having an insulating filling mass. The filling mass might be constituted by materials which solidify by drying, as is the case with magnesium oxide mixed with water-glass, litharge or a similar material. Better results are obtained with an insulating, inorganic thermoplastic material, the use of which for fastening the internal parts of a discharge tube in general is suggested later in this description. Glass and enamel are excellently suitable materials for this purpose, since they excellently satisfy the conditions imposed by the circumstances under which they are used in this case.

As compared with the known construction in which the electrodes are fastened in glass carriers, the construction according to the invention offers the advantage that glass having a much lower softening temperature, as glass of lead borate, may be used for fastening, so that a less strong heating suflices and the electrodes are less attacked.

Tubes according to the invention may be manufactured by placing the objects to be secured on an assembly mandrel in the position which they have to occupy relatively to each other in the tube and placing on these objects the carrying members of which the cavities have been filled beforehand with a soft mass to be hardened later, the supports with which the objects are provided being pressed into the soft mass. Subsequently, the hardening process is carried out and, this being done, the assembly jig removed.

Filling materials which solidify by drying offer the advantage that at the moment when they are applied they are plastic at room temperature. This advantage may also be obtained with the use of glass or enamel. In this case the filling material may be deposited into the cavities of the carriers in the form of a pasty mass containing powdery glass and a mixing liquid.

The heating which is required if glass and similar plastic filling materials are used may be effected electrically when the carrying members are of metal, for example by means of a highirequency magnetic alternating field. Metal: rods may be heated electrically by means of direct con-- nection to a source of supply.

The invention provides also the possibility of electrical heating with carrying members of insulating material. Though the necessary heating may also be obtained with the aid of a gas flame or heat-radiating bodies, this involvesthe drawback that it is difficult to localize the heat so that all sorts of adjacent components are necessarily also heated. According to later developments oi the invention, the rods are provided with one or more additional grooves or longitudinal channels which have laid in them a conductor whichistraversed by an electric current. The joul'ean heat resulting therefrom in the interior of the rod easily penetrates as far as the filling mass without being impartedv to a. considerable extent. to. the further surroundings.

The heating has the efiect of driving out the mixing liquid and softening. the grains of the powdery glass so as to flow together to form a tough homogeneous material. With prolonged heating the material becomes more and more fluidv and easily fills narrow; spaces. It is evident that the temperature. must be so controlled as to prevent the soft material from flowing out of the cavities ordropping ofi. When thoroughly flowed out, it is cooled down, followed at last by removal of the assembly mandrel. The system is thensuited to be placed in the tube.

In cathode ray tubes in which two or more electron rays are generated beside each. other by separate electrode systems the rods may be provided with. twoor more fastening grooves so that a rod may serve tocarry more than one electrode system. 1

In order that the invention may be more clearly understood and. readily carried into effect, it will be. described more fully with reference. to the accompanying drawing.

Figs. 1, 2, 3 and 4 are sectional views of carryingrods.

Fig. is a sectional view of the electrode system of a. tube according to the invention for two electronic rays.

Figs- 6: and. 7 are a longitudinal and a sectional view of an arrangement for electrically heating the rods.

is. a view partly in. section. of a discharge tube embodying the supporting rods of the illvention.

The rod shown in Fig. 1 has a, simple rectangular shape, the cavity for the filling. material having also the form. of a rectangular longitudinal groove. In the case of rods having local cavities the latter may also extend throughout the rod.

In Fig. 2 the rod has the shape of a tube having a longitudinal. seam throughwhich. the supports for the. electrodes may be introduced into the. mass to be hardened. This shape offers the advantage that. thefilling material does. not easilyescape. With the use. of glass as filling material and rods of ceramic materiaL, such as steatite,. the risk of escaping does not exist with a sufliciently careful treatment so that rods having cavities identical to that represented in Fig. 1 may be used aswell.

Fig. 3 shows a rod having two grooves beside each other, which is adapted to a tube with tworay ig- 4 also represents a rod for such a tube which is designed to be arranged between the two systems and for this purpose comprises a groove on each side.

The system shown in Fig. 5 utilizes two rods I and 2 of the type shown in Fig. 2 and two rods 3 and 4 of the type shown in Fig. 3. The electrodes 5 and 6, which may have the form of cylinders or rings, are provided with supports in the form of thin metal rods 1 or strips of which the extremities are set in glass provided in the tubes [1 and 2v and in the rectangular grooves of the rods 3 and 4. The electrodes are thus fastened soas to be unmovable.

The glassv in the. form of powder mixed with a liquid suitable for the purpose, for example water or alcohol, to form a pasty material, is pressed into the grooves and, subsequent to the arrangement of the rods on the supports 1,

vis. transformed by heating into a homogeneous,

viscous mass which after cooling solidifies and tightly adheres. to the surrounding walls. Since in this. case the glass. only serves. as. a binder and a separate member serves as a carrier, the elec-- trodeskeep exactly in. position relatively to each other after removal of. the assembly mandrel. and also later during degassing. Even if the rods would undergo a deformation due to heating, this deformation is not detrimental, since with a simultaneous and. uni-form. heating of the rods (which is not possible with rods which are wholly of glass) these deiormations. are entirely symmetrical.

Figs- 6 and 7 represent twoholders- 3|. and 32 for heating wires which may be. used for softening the filling material. of glass or enamel. These holders arev constituted by a copper bush II in which a piston I2 is placed. Between the piston ['2 and the bush H' is located a tube (3 of percelain or a similar material for the purpose of insulation. The bottom also is covered by an insulating plate M. The piston l2; and the bush 1 l have fastened to them transverse arms i5 and Hi provided with holes H and 18. A wire l9 which serves as a heating element is fastened in these holes by means of screws 20.

A compression spring 22 which keeps the wire l9- stretched maybe arranged in the space below the piston. Whenthe piston i2 is connected to one terminal and the bush H to the other ter minal of a source of electric current, the wire 19- is traversed by a current heating the wire whenthe current isof sufiici'ent intensity. According as the rods to be heated are longer or shorter the wire I9 is longer or shorter and the arms [5' and f6 are waced apart over a greater or smaller distance.

When an electrode system is tobe secured to more than one rod a plurality of holders may be arranged in such manner that the position of each holder correspondsto that of a rod. For this purpose the holders 3i and 32 are rotated by relatively to each other-and screwed to two rings 24 and 25, represented only in part, which may serve. also for the supplyof current. The rings may also be of insulating material, which may be desirable. with a view to connecting the wires. in series with the aid of metal connecting pieces placed on the rings. This series connection ensures a uniform heating of all the wires and thus contributes to the symmetry of the electrode system.

The carrying rod 26; may be heated by the wire l9 clampedin the holder 3|.-. This rod, which is of insulating material, has two grooves, a. groove 2'!- into which fits the: wire t9 and a groove 28 which has placed in it the electrode supports indicated by dotted lines and which has deposited in it the pasty glass powder. On

heating the Wire [9 by electric current this glass powder is transformed into a homogeneous mass which solidifies later and. retains the electrode supports in the groove 28.

Fig. 7 shows in dotted lines an electrode having for example the shape of a cylinder and provided with four supports which are at right angles to each other. This electrode may be secured to four rods, all four of which may be heated simultaneously. For this purpose four holders, each comprising a heating wire, are united to form one assembly. After the elec trodes have been arranged in an assembly mandrel, these four holders, jointly with the fasten-- ing bolts 23, are pushed into the grooves 29 of the rings 24 and 25 so that the wires I9 lie in the grooves 21 and the extremities of the electrode supports lie in thegrooves 28, the wires and supports being then clamped with the aid of nuts.

Instead of the groove, the fastening rods may have a wholly closed channel as a lying-place for the heating wire. In this case a still smaller amount of heat gets lost but the mounting or dismounting of the assembly is effected less quickly, since each time the wires l9 have to be loosened and passed through the tubes. The tube shown in Fig. 8 comprises within an envelope 40, a cathode 4|, an anode 42 and supporting rods 4343 for example of the type shown in Fig. 1. The cathode is supported by metal rods 4444 encircling the bottom of the cathode and having their ends secured within the cavity of the rods 4343. The anode 43 is similarly supported by metal rods 4545 having their ends secured within the rods 4343.

I claim:

1. An electric discharge tube comprising an envelope, a member substantially fixed in space relation thereto and having a tubular portion within said envelope, said portion being provided with a longitudinal cavity extending substantially along the entire length of said member and having an opening communicating with the space within said cavity, a hard filling material in said cavity, a supporting member having a portion thereof extending transversely into said cavity through said opening and aflixed in said material, and a tube element supported by said supporting member.

2. An electric discharge tube comprising an envelope, a member substantially fixed in space relation thereto and having a portion within said envelope, said portion having inner walls defining a longitudinal cavity extending substantially along the entire length of said portion and having a passageway communicating with the space outside said tubular portion, a hard filling material in said cavity and bonded to the walls of said cavity, a supporting member positioned to have a portion thereof extend transversely into said cavity through said communicating passage and affixed in said material, and a tube element connected to and supported by said supporting member.

3. An electric discharge tube comprising an envelope, a member substantially fixed in space relation thereto and having a tubular portion within said envelope, said portion having a longitudinal cavity extending substantially along the entire length ofsaid member and a transverse opening communicating with said cavity, a hardened inorganic thermoplastic filling material in said cavity, a supporting rod having'a portion thereof extending transversely into said cavity through said opening and aflixed in said material,

and a tube element supported by said rod.

4. An electric discharge tube comp-rising an envelope, a rod-shaped carrying member within said envelope and fixed in space relationship thereto, said rod-shaped member having a longitudinal groove extending substantially along the entire length of said portion, a'hardened filling material in said groove and bonded to the said rod member, and a supporting member having a portion extending transversely into said groove and bonded to said bonding material, and a tubeelement supported by said supporting member.

5. An electric discharge tube comprising an envelope, a rod member fixed in space relationship to said tube and having inner walls defining a longitudinal cavity therein extending substantially along the entire length of said member and a longitudinal passageway narrower than said cavity and communicating with said cavity and the spaceoutside of said rod member, a hardened filling material within said cavity and bonded to said rod, and an electrode supporting member having a portion extending transversely through said passageway into said cavity and bonded to said material.

6. An electric discharge tube comprising an envelope, a rod within said envelope and fixed in space relationship thereto and having groove walls in heat exchange relationship, said walls defining two longitudinal grooves and one said groove having a longitudinal passageway extending substantially along-the entire length of said member and communicating with the space outside said rod, a hardened filling material in said one groove bonded to said Walls and an electrode supporting member having a portion extending transversely through said passageway into said one groove and bonded to said material.

7. An electric discharge tube comprising an envelope, a member substantially fixed in space REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,056,035 Beggs Sept. 29, 1936 2,089,044 Thomas Aug. 3, 1937 2,158,845 Ayer May 16, 1939 2,174,853 Bowie Oct. 3, 1939 2,211,602 Lait et al Aug. 13, 1940! 2,212,556 Baier Aug. 27, 1940 

